Oscillation of Second‐Order Canonical and Noncanonical Delay Differential Equations

ABSTRACT In this paper, we investigate the oscillatory behavior of certain second‐order delay differential equations in both canonical and noncanonical forms. We establish new oscillation criteria that extend and enhance existing results addressing cases where previously known theorems do not apply. A key contribution is the introduction of an oscillation‐preserving transformation, which generates novel results and expands the applicability of oscillation criteria. The results are demonstrated through examples, emphasizing their effectiveness and generality in analyzing a wide range of delay differential equations.